While the ancient henges, as Scheduled Ancient Monuments, cannot be damaged or altered in anyway, quarrying would put the wider archaeological landscape at risk.

"Over the last five years our understanding of what a ritual landscape is has been transformed," explained Dr Horton.

"You can't just say 'X marks the spot, this is the henge sitting there isolated'. It is actually part of a complex landscape."

While Dr Horton maintained that Tarmac is a responsible company that would carry out the necessary evaluations and excavations, his concern was that the policy would be one of preservation by removal and recording, rather than preservation in situ.

He pointed out that at the rather more famous Stonehenge site in the south of England recent road plans have been altered at considerable cost to preserve the site's wider archaeological context.

"Everyone accepted the sensitivity of it and the need to preserve the archaeology in situ around it because it is such an important place," he said.

"From my perspective, for the landscape around Stonehenge, which is of equal importance to the landscape around Thornborough, the Government is happy to spend £183m to preserve it in situ, but when it comes to Thornborough, it's a case of lets just leave the lot."

Photo: quarrying activities have slowly eroded the area around the henges since the 1960s. Courtesy Friends of Thornborough Henges.

Director of the Council for British Archaeology, George Lambrick explained just how important the surrounding landscape is in understanding henge monuments.

"By analogy with Avebury or Stonehenge, you can't really understand these key monuments without understanding everything else that's going on around them," said George.

"There is a lot of burial evidence, some small evidence of domestic activity, small but completely significant and we know that these things almost always exist around large sites."

Furthermore, as archaeologist and prehistoric expert Maisie Taylor asserted, the existence of such ancient sites in places where gravel is found, is a well known fact.

"These ritual landscapes, because of the nature of historic settlement, often are on gravel tracts," said Maisie. "So where you get a great river, the whole of it is scattered with these amazing sites and of course they are unbelievably heavily quarried and huge amounts of stuff has gone into the quarries over the years."

"In the past these landscapes have gone and people could plead ignorance, but the problem now is that I don't see how they can plead ignorance. We know these sites are on gravel and they have to acknowledge that they are."